def test_limits_no_return(self):
control = Control()
result = control.limits(0)
self.assertIsNone(result)
result = control.limits(0, 0)
self.assertIsNone(result)
result = control.limits(0, 0, 0)
self.assertIsNone(result)
def test_limits_return(self):
control = Control()
result = control.limits()
self.assertIsInstance(result, tuple)
self.assertEqual(3, len(result))
self.assertIsInstance(result[0], int)
self.assertIsInstance(result[1], int)
self.assertIsInstance(result[2], int)
self.assertEqual(0, result[0])
self.assertEqual(0, result[1])
self.assertEqual(0, result[2])